Secretory and proliferative activities of the prostate gland are largely dependent on androgenic hormones. To understand the mechanism by which androgens regulate gene expression in the prostate, this laboratory has successfully developed and characterized a system using prostate-specific kallikrein genes as a model for such studies. In addition to androgens, other extracellular stimuli such as extracellular matrix, growth factors, and small bioactive molecules also play important roles for biological activities of the gland (normal and pathological). The preliminary data shown in this application demonstrate that the stimuli such as extracellular matrix, zinc, calcium, and phorbol esters indeed, affect the expression of prostate kallikrein genes, independent of or cooperatively with androgens. A number of approaches will be used to elucidate the regulatory mechanism for the kallikrein gene expression as influenced by the stimuli. These will include immunoassay for prostate specific antigen (PSA), Northern blot analysis, Nuclear run on, gel retardation, and DNase footprinting assays. Furthermore, high order of genomic DNA structures (chromatin) and the nuclei matrix are important for regulation of gene expression. Alterations of the nuclear matrix and the chromatin structure may be associated with human diseases including prostate tumor. The effects of androgen on changes in the chromatin structures and nuclear matrix regarding regulation of gene expression in the prostate is poorly understood. The purposes of this proposed project are to use prostate kallikreins as a probe to elucidate the potential control mechanism by which chromatin structure and nuclear matrix affect androgenic induction of the prostate kallikrein gene expression. Therefore, in vivo and in vitro chromatin structures in the 5' flanking region of the prostate kallikrein gene will be characterized by micrococcal nuclease and DNase I footprintings as under androgenic influence. The interactions between prostate kallikrein gene, the nuclear matrix and the androgen receptor will also be analyzed when prostate cells are exposed to androgens. Achievement of these studies should provide valuable insight into gene regulation in prostatic cells by various stimuli.